1. Field
Embodiments of the present invention relate generally to an optic Distributed Antenna System (DAS), and, more particularly, to an optic DAS which is capable of supporting a multi-band, multi-carrier service, rather than a single band or single carrier service, over a single or reduced number of optic core lines.
2. Description of Related Art
A Distributed Antenna System (DAS) is a system which amplifies and sends signals from a Base Transceiver Station (BTS), so that the signals can reach Radio Frequency (RF) shadow zones in areas where radio waves cannot typically be transmitted, such as areas in a large building, a campus, a stadium, a hospital, or a tunnel. In an opposite direction, the system also functions to amplify signals of a terminal in the RF shadow zone, and to send those signals to the BTS.
In a typical optic DAS, a Head End (HE) unit adjusts an RF signal connected to a Base Transceiver Station (BTS)/Bi-Directional Amplifier (BDA) in a wired connection to an appropriate level for each band or each carrier, performs Electronic/Optic (E/O) conversion and optic distribution for each band or each carrier, and sends the RF signal to a Remote Unit (RU) over an optic line. For the purpose of illustration, FIG. 1 shows a configuration of an optic DAS which supports two bands or carriers, in which two optic lines are connected to each RU, and four RUs are provided, therefore requiring eight optic lines. If desired, an HE may be connected to a different number of RUs over a different number of optic lines in order to support a larger number of bands or carriers.
The conventional technology requires a plurality of optic lines for each RU in order to support a multi-band, multi-carrier service. Accordingly, as the number of bands or carriers increases, the number of optic lines for each RU increases. Furthermore, as the number of optic lines increases, a risk of failing in the provision of service because of an error in connecting the optic lines increases. Additionally, there arise problems in that the system construction costs, optic line deployment costs, and operating costs increase, and the operating efficiency deteriorates.